Prevention of Malignant Hypertension in Salt Loaded “S” Dahl Rats With The Calcium Antagonist Nifedipine

Abstract

Female S Dahl rats, fed an 8% NaCl diet from the 6th wk of age developed malignant hypertension and heart hypertrophy in the course of 6 wk on the salt regimen. Simultaneous treatment with nifedipine (300 ppm in diet additional to 8% NaCl) prevented the increase in blood pressure, reduced heart hypertrophy and mortality and improved the impaired renal function in "S" rats. The decrease in hematocrit in salt loaded "S" rats was prevented by nifedipine. The prophylactic effect of the Ca antagonist nifedipine is only partly due to the prevention of increase in systemic vascular resistance. In addition an improvement of failed intrarenal hemodynamics by nifedipine can be postulated. This enables the kidney of S rats to excrete the salt load without increasing blood pressure and plasma volume.